Chery A11. Manual — part 169

Maintenance Manual for Chery·Windcloud

MOTOROLA EFI System

6

6. Electronic Control Unit (ECU)
Purpose:
With microprocessor as core composition,
ECU has a sensor signal input interface, also,
it is an electric control engine control center
for actuator drive circuit, which receives and
processes engine condition signals inputed by
sensors, and sends out control signal to
actuators so as to make the engine work as
per scheduled program and achieve optimum
condition of engine as well as ensure
favorable power, fuel consumption and
emission.



Normal operation voltage: 9-16V


Composition: it has shielded casing and
printed circuit board, which integrates lots of
electronic control units for the control of EFI
system.


Installation: to be fixed by the support of
bracket under pilot trench of front windshield.
Pay attention to waterproofing.

ECU

Functions:

Multipoint group injection
Controlling ignition
Idle speed control
Knocking control
Providing sensors with power supply:
5V/100mA
λ

closed-loop control with self-adaptation

Controlling carbon canister control valve
Air conditioning switch
Engine-failure indication lamp
Engine speed signal output
Failure self-diagnosis with flash code
function
Accepting engine load signal

Troubleshooting: due to the fact that ECU
(electric control unit) has low failure rate, so
generally it is not advisable to replace ECU for
troubleshooting on any problem. Failure of
components such as periphery circuit and
sensors shall be checked and solved firstly. Do
not replace ECU until all periphery components
are confirmed to be fault-free.

Maintenance Manual for Chery·Windcloud

MOTOROLA EFI System

3. ECU Pins Definition:

A

B

Ground

Ignition coil 2

Air

conditioning

pressure

switch

Injector 3

Rotation

speed

output

Fuel

pump

control

Radiator fan

Ground

Crankshaft

position

sensor positive

Vehicle

speed

sensor

Crankshaft

position sensor

signal negative

Serial

communication

interface

Bootstrap

LPT

Standard

5V power

output

Main

power

Sensor

ground

Idle stepper

motor 1B

Idle stepper

motor 1A

Compressor relay

Ground

Condensor

relay

Idle stepper

motor 2A

Idle stepper

motor 2B

Intake

pressure

Ignition coil 1

Injector 1

Injector 4

Injector 2

Throttle

position sensor

Intake air

temperature

Air

conditioning

temperature

sensor input

Water

temperature

sensor

Oxygen

sensor

signal

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Maintenance Manual for Chery·Windcloud M

OTOROLA EFI System

7. Electric Fuel Pump

Purpose: to carry fuel from fuel tank to

engine at a certain pressure and flow rate

(different in systems).

Composition and principle: electric fuel

pump is coaxially installed with pump motor

in the same casing. It is constituted by direct

current motor, vane pump and end cover

(integrating check valve, decompression

valve and anti-electromagnetism

interference component). The maximum

pressure of electric fuel pump outlet is

determined by decompression valve between

450-650kPa, while the pressure of entire

fuel system varies with manifold pressure.

The difference between system pressure and

manifold pressure is determined by fuel

pressure adjuster, for MOTOROLA EFI
system it is 250kPa in general.

Caution: if fuel tank is in longstanding fuel

starvation or fuel shortage, fuel pump will

suffer from bad lubrication, which results in

fuel pump cementing, especially for engines

using CNG and LPG.

Fuel temperature has fairly big impact on

fuel pump performance, in case of

longstanding operation under high

temperature condition, when fuel

temperature is higher than a certain value,

the pressure of fuel pump drops dramatically,

in this case, if engine fails to start when

heating vehicle, please check carefully

whether the high temperature performance

of fuel pump is out of condition.

Electric fuel pump

Main power

Fuel pump relay

Fuel pump

Circuit diagram of electric fuel pump

Pins: electric fuel pump has 2 pins, which

connecting with fuel pump relay. “+” and

“-” are marked on the fuel pump housing

beside both of the 2 pins, which indicates

connecting with anode and cathode

respectively.

ECU A21# pin controls fuel pump relay.

Troubleshooting: generally the failure of

fuel pump appears as insufficient fuel

pressure or no pumping-out of fuel. In case

of troubleshooting, system fuel pressure

shall be checked to see if it is within the

scope of specified value and if pipeline is

leaking.

In addition，fuel tank’s positive pressure and

negative pressure will have impact on fuel

system.

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Maintenance Manual for Chery·Windcloud

MOTOROLA EFI System

8. Electromagnetic Injector

Purpose: according to ECU instruction,

injector ejects fuel within the stipulated time,

by which means providing engine wtih fuel

and atomising it.

Composition and principle: ECU sends out

electric impulse to injector coil, forming

magnetic field force. When the magnetic

field force increases well enough to

overcome resultant force of retracing spring

pressure, pin valve gravity and friction, pin

valve starts to lift, and the fuel injection

begins. The maximum lift range of pin valve

shall not exceed 0.1mm. In case fuel

injection impulse is cut-off, the pressure of

retracing spring enables pin valve to switch

off again.

Installation hints: a certain injector shall

apply to a certain pin without mixing use.

In order to facilitate installation, it is

recommended to apply uncontaminated

silicon-free engine oil to the surface of

upper O-ring connecting with fuel

distributing pipe. Be careful not to let engine

oil contaminate interior or squirt hole of

injector.

 Install injector into injector seat in the

direction perpendicular to the seat, and then

fix the injector on it with clamp.

Caution: for long-term idle vehicle,

gasoline cementation in injector results in

failure of normal startup of vehicle after

long-term idling. In this case please check

carefully to see if the injector cements.

Failure diagnosis: EFI system of A11 does

not apply failure diagnosis to injector itself,

but to injector driver stage. When the driver

stage of injector is in short circuit or excess

load status to accumulator, in short circuit

and open circuit status to ground, the failure

mark is set. At this point, shut down oxygen

sensor closed-loop control and its

self-learning precontrol, the last

self-learning data is valid. After

troubleshooting, failure mark restores.

Working pressure: 350 kPa

Injector resistance: 11-16

Ω

Electromagnetic injector figure

Main power

Injector set

Circuit diagram of electromagnetic injector

Pins: each injector has 2 pins. Of which, the

one marked with positive sign beside

housing shall be connected with 87# pin of

fuel pump relay output terminal; the other

shall be connected with A9#, A2#, A10# or

A1# pin of ECU respectively.

Troubleshooting: generally injection

nozzle’s non-smooth fuel injection and

defect atomization is caused by long-term

application of engine. To solve this

problem, periodical cleaning of injection

nozzle is required.

Short circuit, open circuit in interior coil of

injection nozzle may also result in fuel

injection system failure.

Check to see if there is short circuit or open

circuit in system line.

Due to long-term usage of nonconforming

fuel, the said fuel cements on squirt hole of

injection nozzle, which is liable to cause

failure of idle speed unsteadiness.

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